Conventionally, a metering feeder for metered supply of a material such as a powder/granular material or the like as illustrated in Patent Literature 1, for example, has been developed.
This prior-art metering feeder has a configuration in which an inner cylinder and an outer cylinder are arranged concentrically, a gap is provided between a lower end of the inner cylinder and a bottom plate of the outer cylinder, whereby an annular transport space for a powder/granular material is provided between the inner and outer cylinders, a central rotating blade is provided on the bottom plate around a center upright rotating shaft of the bottom plate, an outer rotating ring along an inner periphery of the outer cylinder is provided at a tip end of the rotating blade, a plurality of outer rotating blades directed toward an inside are provided on the ring, a rotating disc having an upper surface on the same plane as an upper surface of the bottom plate is provided, a powder/granular-material discharge groove concentric with the disc is provided on an upper surface of the disc, the groove is disposed over an inside and outside of the outer cylinder, and a single powder/granular-material discharge scraper is fixed in the groove on an outside of the outer cylinder.
This metering feeder is configured such that, by rotating the central rotating blade and the rotating disc together, the powder/granular material in the annular transport space is scraped and thrown into the powder/granular-material discharge groove of the rotating disc by the outer rotating ring by means of rotation of the central rotating blade, and the powder/granular material having been thrown into the discharge groove is metered and supplied by the single powder/granular-material discharge scraper to an outside of the rotating disc.